I have at table where a field called taxing_district_code is a varchar2(16). In the following select I get 58 rows

select wr_no, revision_no, point_span_seq_id, taxing_district_code
from wr_point_span
where wr_no = 4317 and revision_no = 2 and taxing_district_code = 474

if I change the where clause to:

select wr_no, revision_no, point_span_seq_id, taxing_district_code
from wr_point_span
where wr_no = 4317 and revision_no = 2 and taxing_district_code = '474'
order by wr_no, revision_no, point_span_seq_id

I only get 17 rows. The only difference is putting ' around the 474 value.

Can someone explain this?